Adaptive Cruise Control (ACC) systems use an on-board sensor (usually RADAR or LIDAR) to detect the distance between the host vehicle and a vehicle ahead of the host vehicle (the lead vehicle), and the relative speed difference between the vehicles. The system then automatically adjusts the speed of the host vehicle to keep it at a pre-set distance behind the lead vehicle, even in most fog and rain conditions. Typically, the host vehicle driver can set a desired/minimum following distance and/or a time gap to be maintained between vehicles. The ACC generates automatic interventions in the powertrain and/or braking systems of the host vehicle to slow the vehicle as necessary to maintain the selected minimum following distance.